The present invention relates generally to interface devices for allowing humans to interface with computer systems, and more particularly to computer interface devices that allow the user to provide input to computer systems and allow computer systems to provide haptic feedback to the user.
A user can interact with an environment displayed by a computer to perform functions and tasks on the computer, such as playing a game, experiencing a simulation or virtual reality environment, using a computer aided design system, operating a graphical user interface (GUI), etc. Common human-computer interface devices used for such interaction include a mouse, joystick, trackball, steering wheel, stylus, tablet, pressure-sensitive sphere, or the like, that is connected to the computer system controlling the displayed environment. Typically, the computer updates the environment in response to the user""s manipulation of a physical manipulandum such as a joystick handle or mouse, and provides visual and audio feedback to the user utilizing the display screen and audio speakers. The computer senses the user""s manipulation of the user object through sensors provided on the interface device that send locative signals to the computer. For example, the computer displays a cursor or other graphical object in a graphical environment, where the location of the cursor is responsive to the motion of the user object.
In some interface devices, force feedback or tactile feedback is also provided to the user, more generally known herein as xe2x80x9chaptic feedback.xe2x80x9d These types of interface devices can provide physical sensations which are felt by the user manipulating a user manipulandum of the interface device. One or more motors or other actuators are coupled to the joystick, mouse, or other device and are connected to the controlling computer system. The computer system controls forces on the joystick or mouse in conjunction and coordinated with displayed events and interactions by sending control signals or commands to the actuators. The computer system can thus convey physical force sensations to the user in conjunction with other supplied feedback as the user is grasping or contacting the interface device or manipulatable object of the interface device.
Low-cost haptic devices tend to provide tactile feedback, in which forces are transmitted to a housing or portion thereof and felt by the user, rather than kinesthetic feedback, in which forces are output directly in the degrees of freedom of motion of the interface device. For example, many currently-available gamepad controllers include a spinning motor with an eccentric mass, which outputs vibrations to the housing of the controller in coordination with events occurring in a game. In some haptic mouse devices, particular areas on the housing of the mouse can be vibrated in accordance with interaction of a controlled cursor with other graphical objects, which the user feels by touching those housing areas. These tactile devices are typically less sophisticated than kinesthetic devices and therefore are much less expensive to produce.
In addition, haptic feedback devices, such as mice in particular, can be made less costly to produce by making them relative positioning devices rather than absolute positioning devices. For example, a standard computer mouse is a relative device which provides only a change in mouse position to the host computer to control a cursor. This allows the mouse to be freely lifted from the reference surface and requires simpler encoder sensors or the like. Absolute devices, in contrast, are often constrained to an absolute sensing range and may require more expensive sensors in some embodiments.
One problem with such inexpensive haptic controllers is their limited ability to convey certain types of force sensations to the user. For example, many tactile mice are incapable of providing spring and damper sensations in the degrees of freedom of the mouse. These types of devices tend to be limited in producing other spatially-based force sensations as well. Textures, for example, are force sensations which are based on the position of a controlled cursor in a graphical environment. If the cursor is moved over a textured area, the user of the haptic device should feel forces that are output in coordination with the cursor moving over each texture bump where it is located in the graphical environment. Texture sensations are often effectively produced by imparting a damping or spring force on the mouse at regularly-spaced positions; tactile devices, however, cannot output damping or spring forces. Furthermore, it can be difficult to correlate forces with the location of texture features or other spatially-activated haptic sensations when a relative input device is used. Thus, some tactile devices of the prior art may instead provide a spatially-independent vibration to simulate a texture. Such vibrations are based on a time-based source waveform, not the motion or location of the device or the cursor, and thus tend to feel unrealistic to the user when a texture sensation is desired.
The present invention is directed to a low-cost haptic feedback device connected to a computer system, the device being a relative device that provides spatially-based sensations such as textures in correlation with a displayed graphical environment.
More specifically, the present invention relates to a haptic feedback interface device that is coupled to a host computer which implements a graphical environment. In a preferred embodiment, the device, such as a mouse, includes a housing that is physically contacted by the user, a sensor device coupled to the housing and detecting the movement of the device in a planar workspace, and an actuator coupled to the housing and applying a force to the user along an axis approximately perpendicular to the planar workspace. A local processor reports relative sensor data to the host processor, representing a relative change in position of the device, and receives force information from the host processor. The force information causes a texture sensation to be output by the actuator, the texture sensation providing a force to the user based on an interaction of a cursor with a texture field in said graphical environment, where the texture field includes predefined locations that are at least approximately spatially correlated with the forces from the texture sensation.
Preferably, the texture sensation includes a pulse that is output on the housing each time the cursor crosses a predefined region in a texture field. Each of said regions can include two borders, wherein the pulse is output when the cursor crosses one of the borders and enters the region, and when the cursor crosses said other border and exits the region. A texture command from the host can include parameters of width, spacing, and sense, where the sense is a direction of up or down.
In some embodiments, the local processor can model a position of the cursor when the cursor interacts with the texture field, where the modeled position is used for determining the force output to the user. The force information received from the host computer can include a gating command that indicates to the local processor to activate the texture sensation, and another gating command can be sent to indicate to the local processor to deactivate the texture sensation. The modeled position can be a ballistic position of said cursor that is based on a velocity of the mouse device in the workspace. The host can determine a host ballistic position based on the sensor data, where the host uses the host ballistic position to display the cursor in the graphical environment and to determine when the texture sensation should be activated and deactivated.
In preferred hardware implementations, the actuator applies an inertial force approximately along the axis perpendicular to said planar workspace by moving an inertial mass, wherein the inertial force is transmitted through the housing to the user. In other embodiments, the actuator moves a cover portion of the housing approximately perpendicularly to the planar workspace, where the cover portion contacts a portion of the user""s hand. Or, the actuator can move a button of the device approximately perpendicularly to the planar workspace.
The present invention provides a low-cost, relative haptic feedback device for providing force sensations. The device can provide relative motion data to the host computer like a standard mouse, but can also provide spatially-based force sensations such as texture sensations. The spatially-based sensations are correlated with locations in the graphical environment and thus feel compelling to the user.
These and other advantages of the present invention will become apparent to those skilled in the art upon a reading of the following specification of the invention and a study of the several figures of the drawing.